1. Field of the Invention
The present invention relates to an apparatus having a plurality of installation parts and a device unit for installation to each installation part of the apparatus.
2. Discussion of the Background
Generally, when dealers handle or users use various apparatuses, consumable items and replacement parts thereof are kept in stock. For example, when handling or using image forming apparatuses of various kinds, the dealers or the users generally have spare devices of a development device, etc., in stock. The dealers and the users therefore must keep a storage space or facility for such spare devices.
In particular, in an image forming apparatus such as a color laser printer having a tandem-type configuration, an image forming device, e.g., a development device, etc., is provided for forming each of black, cyan, yellow, and magenta toner images, that is, four development devices are provided. Therefore, when a user uses the image forming apparatus, spare development devices, etc., for respective colors are kept in stock, so that the number and the kinds of spare devices in stock is inevitably increased. As a result, a larger storage space or facility is necessary, and management of storage items is relatively complicated.
To cope with the above-described problem, an image forming apparatus has been proposed, in which development device units having a common configuration are used for forming toner images of respective colors. A plurality of installation parts, to which the development device units for forming toner images of respective colors are installed, are provided in the image forming apparatus, and each installation part is configured such that the development device unit can be detachably attached. Once such common development device units have been installed to respective installation parts of the image forming apparatus and when the image forming apparatus is operated, developers of corresponding colors, such as toner and ink, are supplied to respective development device units from the main body of the image forming apparatus.
In the above-described image forming apparatus, because the common development device units are used in the plurality of installation parts for forming toner images of respective colors, even when a development device unit uninstalled from one of the installation parts is installed to another one of the installation parts, the development device unit is properly operated. In this case, if the development device unit once installed to and used at an installation part to which toner of a certain color is supplied is installed to another installation part to which toner of a different color is supplied, because the toner of a certain color previously used in the development device unit remains therein, mixing of the toners of different colors is caused in the development device, so that color mixture is caused albeit slightly in a resulting image.
To cope with the above-described color mixture problem, an image forming apparatus has been proposed, in which when a device unit once installed to one of the installation parts of an image forming apparatus is installed to another installation part of the image forming apparatus, a predetermined operation of the image forming apparatus is restricted or a warning is generated.
For example, Japanese Patent Laid-open publication No. 2001-83862 describes an image forming apparatus in which a plurality of process cartridges, each having at least a development device, are installed to respective installation parts, and toners of different colors are supplied to respective process cartridges from a plurality of toner replenishing devices. Regardless of the colors of toners supplied to respective process cartridges installed to the installation parts, a common unit is used for each of the process cartridges, and each process cartridge is configured to freely attachable to and detachable from any installation part. A storage device is provided to each process cartridge, and the information as to the color of toner first supplied to the process cartridge is stored in the storage device. When a process cartridge in which the information as to the color of the toner first supplied thereto has been stored in the storage device is installed to an installation part to which toner of a different color is supplied, the image forming apparatus does not operate or a warning is generated to inform that the process cartridge has been installed to an incorrect installation part. Thus, in the image forming apparatus, even when a user has erroneously installed a process cartridge once installed to and used at an installation part for a certain color to another installation part for another color, the image forming apparatus is not operated or a warning is given to the user, so that the inconvenience, which might have been caused due to such erroneous installation of the process cartridge, can be voided.
In the above-described image forming apparatus, however, because the information as to the color of toner first supplied to each process cartridge is electrically written in the storage device of the process cartridge, unless installation of the process cartridge has been completed, it is not known that the process cartridge has been installed to a wrong installation part, which is inconvenient.
The above-described JP also describes a mechanical device for storing the information as to the color of toner first supplied to each process cartridge. A plurality of protrusion parts is provided to the process cartridge, and when the process cartridge has been first installed to an installation part of the main body, a protrusion part corresponding to the installation part is bent from the side of the main body. The bent protrusion part of the process cartridge is detected using a detector such as an optical sensor, and a controller at the side of the main body determines the installation part to which the process cartridge has been first installed, that is, the color of toner first supplied to the process cartridge, based on the detection result. In this case, however, if a protrusion part of a process cartridge is bent or damaged for some reason other than installing the process cartridge to an installation part and when the process cartridge has been installed to an installation part, if the operation of the image forming apparatus is restricted or a warning is generated, the reason of restriction or warning is unknown to the user, which is troublesome. Further, the bent or damaged protrusion part of the process cartridge cannot be restored to the original state, so that it is hard to reuse the protrusion part as the mechanical device for storing the information as to the color of toner first supplied to the process cartridge.
Furthermore, even if the plurality of protrusion parts is kept together and is arranged in one location, it is relatively difficult to recognize the information as to the color of toner first supplied to the process cartridge based on the outer appearance of the plurality of protrusion parts at first glance, so that the possibility that the process cartridge is installed to a wrong installation part cannot be avoided. That is, even when the user could recognize that the process cartridge has been installed to a wrong installation part, it is relatively hard to recognize the correct installation part for the process cartridge from the outer appearance of the process cartridge, which is inconvenient.